WILTIMS #194: Target aquired

TIL: Anisocytosis is the variation in size of red blood cells (RBCs). RBCs normally have a very consistent morphology, so when they look different it is an easy indicator of pathology. RBCs are recycled about every 4 months, meaning that about 1% of the circulating RBCs should be brand new immature cells. Too many young RBCs (which look bigger and greyer) mean that the body is producing more red blood cells (likely in response to their destruction in forms of anemia). To Too few immature RBCs can indicate other underproduction anemias.

Some of the morphological changes that can occur include the formation of very faint RBCs, due to disorders of hemoglobin synthesis or iron deficiency; sickle cells, which are formed due to aberrant hemoglobin polymerisation; and target cells, which produce an extra large cell membrane resulting in a extra fold that makes them look like targets.

The pictures to the right show all of the variations I described above. In order: an immature RBC (polychromatophilic macrocyte), faint RBCs from severe iron deficiency (hypochromic microcytes), sickle cells, and target cells.